According to the DNR, the jellyfish are not harmful to humans and are believed to have a small impact on the aquatic environment.

They are not native to Michigan or even North America, according to the DNR, and are believed to be native to China and Asia.

"However, this species has been found throughout most of North America for well over a century and is considered to be a nonharmful member of our aquatic communities, and certainly an intriguing one," the DNR said.

The first time jellyfish were documented in Michigan was in 1933 from the Huron River. Today, they can be found in most Michigan lakes and streams, and are usually spotted in the late summer and early fall.

Their life cycle includes:

• Jellyfish spend winter in bodies of water in a podocyst resting stage
• As conditions become more favorable, they podocysts develop into polyps and continue the life cycle with asexual reproduction
• By late summer, polyps develop into the medusa stage which most resembles a free-swimming jellyfish

"These are the sightings that often trigger calls to local DNR offices from curious spotters who have caught the rare glimpse of the invertebrate," said Tim Cwalinski, the DNR's northern Lake Huron manager. "Though freshwater jellyfish do have stinging cells like the marine species, their tiny size means they lack the ability to sting, and so they're not harmful to people. It is also believed to be unlikely that freshwater jellyfish could consume enough zooplankton in our bodies of water to negatively compete with fish species.
"If you're among those to observe a single medusa stage or colony of freshwater jellyfish this year in our lakes or slow-moving streams, consider yourself fortunate, don't panic, and understand this is simply an invertebrate that has inhabited most of our waterways for a century."